System of electrical distribution.



No. 769,991. PATENTED SEPT. 13, 1904. W. L. R. EMMET.

SYSTEM OF ELECTRICAL DISTRIBUTION.

' APPLICATION FILED FEB. 9. 1900.

N0 MODEL, 3 SHEETS-SHEET 1.

PATENTED SEPT. 18, 1904.

W. L. R. EMMET. SYSTEM OF ELECTRICAL DISTRIBUTION. APPLICATION FILEDFEB. 9. 1900.

NO MODEL.

3 SHEETS-SHEET 2.

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lulllimi l' No; 769,991. PATENTED SEPT. 13, 1904. W. L. R. EMMET. SYSTEMOF ELECTRICAL DISTRIBUTION.

APPLIOATION FILED FEB. 9, 1900.

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No. 769,991. Patented September-13, 1904.

UNTTED STATES PATENT OFFICE.

IVILLIAM L. R. EMMET, OF SCHENECTADY, NEIV YORK, ASSIGNOR TO THE GENERALELECTRIC COMPANY, A CORPORATION OF NEIV YORK.

SYSTEM OF ELECTRICAL DISTRIBUTION.

SPECIFICATION forming part of Letters Patent No. 769,991, datedSeptember 13, 1904. Application filed February 9, 1900. Serial No. 4,605(No model.)

To HY/171107" it y mwern: causing the subdivisions of the respective 5Be it known that I, IVILLIAM L. R. EMMET, windings to be cut into andout of circuit disa citizen of the United States, residing atsimultaneously or in succession. Thus, for

Schenectady, in, the county of Schenectady example, in a quarter-phasesystem theelecand State of New York, have invented certromotive force onone side of the system is tain new and useful Improvements in Systemsfirst varied, then the electromotive force on of ElectricalDistribution, of which the folthe other side, and so on. If a rotaryconlowing is a specification. verter were fed from this system, itsdirect- The invention hereinafter set forth relates current voltagewould be affected by each va- I to certain improvements in theregulation of riation of electromotive force on the different multiphasealternatingcurrent systems of sides of the quarter-phase supply systemand distribution and to an apparatus for carrying would have a valueintermediate between the this regulation into effect. Although parvaluescorresponding to the greater and less ticularly useful with multiphasesystems, it is electromotive forces on the alternating-sup- I5 to beunderstood, however, that myinvention, ply system. It will thus be seenthat for at least as to some of its features, is not limeach tap broughtout from the alternating- 5 ited to use in connection with such systemscurrent-supply winding there are two voltages only, but is capable, onthe contrary, of much on the direct-current side of the converter tobroader application. correspond. In case the system is three- 20 Where amultiphase circuit is used to feed phase the number of gradations ofvoltage a translating device-such, for example, as a obtainable is threetimes as great as the num- 7 rotary converterit is often desirable toher of steps on any transformer or compenchange the electromotive forceof the altersator, as will readily be seen, while the numnating currentby suitable gradations. In her of steps obtainable with multiphase our-2 5 order to effect this result, transformers or rent of a higher orderwill be larger in procompensators having a variable ratio beportion.tween their primary and secondary electro- An important feature of myinvention is motive forces are commonly employed. This the means which Iemploy for changing the variable ratio of electromotive forces may beconnections from point to point in the wind- 30 obtained by subdividingthe Winding from ings of an alternating-current-supply system.

which the secondary electromotive force is In cases where dividedwindings have heretoderived. In such cases the number of differfore beenemployed considerable difficulty has cut electromotive forces obtainablehas herearisen in the endeavor to prevent serious tofore been limited tothe number of subdishort circuits in changing the connections be- 3 5visions of each of the windings referred to. tween adjacent points inthe winding without Where it is desired to obtain a large number at thesame time breaking the main circuit. 8 5 of small gradations ofelectromotive force, Various artifices have from time to time been thisoperates as aserious drawback, since it is employed, nearly all of whichdepend for often not convenient to put a sufficient numtheireifectiveness upon limiting the amount 40 her of turns in the winding ofthe compenof current set up by such short circuits. My

sator or transformer to give the requisite improvement in thisconnection is a radical 9 number of steps, or if the winding haveasufdeparture from the practice heretofore obficient number of turns'itmay be troublesome taining and consists in snapping the points of andexpensive to construct a switch which connection of the main circuitfrom one tap 45 will handle the current and which can be to another of adivided winding or source, so

fitted with the requisite number of steps. that the are formed inpassing out of engage- These difficulties I avoid by providing the mentwith one contact is not interrupted unmultiphase system withtransformers or comtil engagement is made with the next. The pensatorshaving subdivided windings and are thus preserves the continuity of thecur rent while the circuit-changing operation is taking place and is ofsuch low resistance that except in the case of a low-voltage circuit itproduces no appreciable fluctuation in the current.

Although I have thus pointed out in a general way the nature of myinvention, its points of novelty are to be determined by reference tothe claims appended hereto, while for a better understanding of itsdetails reference may be made to the following description of anembodiment of the same, taken in connection with the accompanyingdrawings, in which- Figures 1, 2, and 3 are various views of a switchfor carrying my invention into operation, and Figs. 4 and 5 areexplanatory diagrams.

Although an apparatus operating in accordance with my invention isspecifically illustrated in Figs. 1, 2, and 3, it will perhaps be betterunderstood by first referring to diagrams 4 and 5, illustrating its modeofoperation, before referring to the details of the switch itself.

Fig. 4 illustrates a two-phase alternatingcurrent system, current beingsupplied over transmission-lines 1, 2, 3, and 4to the primary windings 56 of suitable transforming devices, which in this instance are shown asordinary transformers. It will of course be understood that compensatorsmay be employed, if desired, without departing from the spirit of myinvention, and therefore wherever herein I speak of a transformer Iimply also the possible substitution of a compensator or othertransforming device.

Secondary windings 7 8 are arranged in the ordinary manner in inductiverelation to the primary windings 5 6, respectively. Each of thesewindings is subdivided by means of taps leading out to sets of fixedcontacts 9 10, arranged, respectively, in arcs of circles. The number ofthese contacts may be chosen with regard to the necessities of theparticular case in hand. V

Each set of contacts has a cooperating switcharm arranged to move overthe contacts in succession, this switch-arm being electrically connectedto the main circuit. The switcharm 11 is shown in Fig. 4 as cooperatingwith a set of contacts 9 and is connected with the multiphase mains 12,the other conductor, 13, corresponding to this phase being connected toone end of the secondary 7. In a similar manner a switch-arm 14cooperates with the circular row of contacts and is connected to one ofthe conductors 15 of the other phase of the alternating-current system,the other conductor, 16, of this phase being connected to the end of thesecondary 8 in a manner similar to the connection of the conductor 13 tothe secondary 7 of the first phase.

The switch-arm 11 is shown as being on the third contact from the end ofits set of fixed contacts, while the switch-arm 14 is shown as on thesecond contact from the end of its corresponding set of fixed contacts.Suitable apparatus, such as shown in Figs. 1, 2, and 3,

is provided for moving these switch-arms 11 and 14 in succession, themovement being such in the case indicated in Fig. 4, for example, as totransfer the switch-arm'14 to the third contact from the end, then totransfer the switch-arm 11 to the fourth contact of its set of contacts,then to transfer the contactarm 14 to the fourth contact of its set, andso on. In this way the voltages impressed on the multiphase mains 12,13, 15, and 16 will first be balanced, then one will be increased so asto produce an unbalanced condition, then the other will be increased toan equality with the first, thus alternately balancing and unbal. ancingthe system to a slight extent, at the same time progressively increasingits resultant voltage. If the system supply a rotary converter, asindicated diagrammatically at 17, the direct-current voltage of theconverter will increase with each variation of voltage on itsalternating-supply mains.

Fig. 5 shows the use of a double snap-switch in connection with asingle-phase system. In this case two transformers 18 and 19 areconnected in multiple, while the corresponding secondaries 20 and 21 arein series. The respective secondaries have their free ends connected totwo sets of fixed contacts, respectively, and two contact-arms operatein connection therewith in the same manner as shown in Fig. 4. By reasonof the arrangement thus shown a large number of voltage gradations maybe obtained from two cooperating dial-switches of the nature indicated,

thus avoiding the difficulty attendant upon the use of a single largedial-switch.

A form of switch which I have found useful in carrying out theoperations thus indicated is illustrated somewhat in detail in Figs. 1to 3, inclusive. Fig. 3 is an enlarged view of the main portion of theswitch. A circularly-arranged series of fixed contacts is shown at 22and is supposed to be connected by taps to appropriate points in thewinding of a source of electromotive force. The switcharm 23, whichcooperates with. these contacts, is shown as broken off at 24; but itsrelation to the contacts will be readily understood by reference to Fig.l, in which the switcharm is shown as extending from its pivot 25 towarda row of contacts and terminating in a point 26, which moves againstspring projections 27, forming part of the fixed contacts. Motion istransmitted to the contact-arm 23 through a spring connection with thepositively-rotated member 28, connected by meansof a worm-wheel 29 and aworm 30 to a rotatable shaft 31. This shaft may be set in motion by theoperator in any suitable manneras, for instance, by the employment of ahandwheel 32. The member 28 is mounted on the same axis with thecontact-arm 23 and is in.

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fixed relation to the worm-wheel 29, the contact-arm 23 being in movablerelation to the worm-wheel 29 and freely movable with respect to themember 28 except for the restraint imposed by means of its springconnection with this member. This spring connection has a tendency tomaintain the contact-arm 23 in a central position with respect to themember 28, and any suitable arrangement for effecting this result may beemployed. I find it convenient, however, to connect a lug 32 on theswitch-arm 23 with springs 33 and 34, attached, respectively, to hollowprojections 35 36, carried by the member 28, the connections being madeby means of adjustable rods 37 and 38. In order to enable energy to bestored in the springs 33 and 34 preparatory to the snapping of theswitch-arm from one fixed contact to another, suitable locking means isprovided for retaining the switch-arm temporarily in its variouspositions of rest. This locking means consists of an annulusconcentrically arranged with respect to the row of fixed contacts anddrilled with holes opposite each fixed contact, these holes cooperatingwith a locking-pin carried by the switch-arm 23. The locking-pin isshown in side elevation at 39 and is carried by a closed tube 40,somewhat resembling a stuffing-box and fixed in any suitable manner tothe switch-arm 23. The pin 39 is provided with a shoulder 41, againstwhich acts a spring 42. A bushing 43 is screwed into the sleeve 40 andserves to compress the spring, which by its pressure upon the shoulder41 urges the pin out of the shell 40 and toward the annulus 44. Ashoulder on the tube 40, operating in connection with the shoulder 41 onthe pin, serves to limit the distance which the pin may project from theshell 40. The upper end of the pin 39 is provided with an antifrictionroller 45, mounted on an axis at right angles to the axis of the pin.The upper portion of the pin, against which bears one end of the roller,is flattened and lies against the outer surface of a sector-shapedcam-plate 46, carried by projecting lugs 47, integral with the free endof the member 28. Set screws 48 pass through the outer ends of themember 28, as shown in Fig. 2, and project inwardly, so as to serve aspoints of engagement between the contact-arm 23 and the member 28.Checknuts 49 serve to keep the set-screws from jarring loose.

In order to operate the switch mechanism just described, a rotatingmovement is communicated to the worm-wheel 29 through suitablemanipulation of the hand-wheel 32, carried by the worm-shaft 31. Thecontact-arm 23 is normally locked in position by reason of theengagement of the locking-pin 39 with the perforated annulus 44. hen,therefore, the worm-wheel 29 is rotated by the means described, themember 28 carried thereby likewise rotates and moves away from a centralposition with respect to the contact-arm 23, thereby putting a stressupon one or the other of the centering springs 33 34. As the member 28moves relatively to the contact-arm 23 the antifriction-roller 45,carried by the locking-pin 39, is urged out by the cam-surface 50, whichis pushed under the roller by the motion of the member 28. Thelocking-pin 39 is thus gradually withdrawn from its engagement with theannulus 44, and thus releases the contact-arm 23. At about the same timeone of the set-screws 48 brings up against the contact-arm 23 and forcesit out of its frictional engagement with one of the fixed contacts 22,whereupon being then free to move it springs forward under the influenceof one of the springs 33 34, which has been previously put under stress,as described. The contactarm 23 is thus impulsively urged intoengagement with the next fixed contact and toward into the next hole inthe annulus 44 in case it.

is urged far enough forward, and thus locks the contact-arm 23 in itsnew position preparatory to a repetition of the operation described. Theset-screws 48 are adjusted so that the switch-arm 23 is snapped forwardso that its locking-pin reaches a hole in the annulus. Further motion ofthe switch-arm by the operating mechanism then causes a repetition ofthis action. It will thus be seen that the contact carried by thecontact-arm 23 is snapped from one fixed contact 27 to another, in doingwhich an arc is formed which preserves the continuity of the circuitwhile the change in connections is being made. The resistance interposedby this are is generally so low as to have no appreciable effect uponthe volume of current flowing, and owing to its short duration, due tothe snapping action of the contact, its destructive influence upon thecooperating contacts is negligible.

Fig. 1 shows two transformers, each provided with a dial-switch 51 ofthe type described, the actuating-shafts of the switches being connectedtogether by a flexible or universal joint 52. The coupling of theapparatus is such that the movable contacts of the switches operatedissimultaneously, so as to produce alternate or successive variationsof voltage in the respective circuits controlled by the switches. Thenature of this mode of regulation has been fully described in connectionwith Fig. 4 of the drawings, so that no further remarks in thisconnection are necessary.

Although for the purpose of making clear the nature and mode ofoperation of my invention 1 have described specifically an embodiment ofthe same which 1 at present believe to be most-useful in practice, I donot, therefore, wish to be limited in the construction of my claims tothe particular organization and relation of parts shown, but, on thecontrary, I desire that as broad a construction as possible shall begiven to my claims consistent with the state of the art.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1. The combination of a plurality of dialswitches having a quick breakaction, an op crating-shaft for each switch, and connecting means forsecuring simultaneous rotation of said shafts and dissimultaneousoperation of the switches.

2. The combination of a plurality of stepby-step switches, means forgiving a quick break action to each switch, and means fordissimultaneously operating said switches.

3. The combination of a plurality of transformers, a set of stationarycontacts for each transformer, connections between each transformer andits respective set of contacts, a movable contact cooperatively arrangedwith respect to each set of stationary contacts, and connections betweenthe movable contacts for causing a dissimultaneous motion of the movablecontacts.

4c. The combination of a plurality of transformers, a set of stationarycontacts for each transformer, connections between each transformer andits respective set of contacts, a movable contact cooperatively arrangedwith respect to each set of stationary contacts, and connections betweenthe movable contacts for causing a successive motion of the movablecontacts.

5. The combination of a plurality of transformers, a set of stationarycontacts for each transformer, connections between each transformer andits respective set of contacts, a movable contact cooperatively arrangedwith respect to each set of stationary contacts, and means for causing achange of connections due to motion of one of said movable contacts totake place dissimul taneously with respect to change of connections dueto motion of another movable contact.

6. The combination of a plurality of transformers, a set of stationarycontacts for each transformer, connections between each transformer andits respective set of contacts, a movable contact cooperatively arrangedwith respect to each set of stationary contacts, and means for causing achange of connections due to motion of one of said movable contacts totake place alternately with respect to change of connections due tomotion of another movable contact.

7. The combination of a plurality of sets of annularly-arrangedstationary contacts, a cooperating contact-arm for each set, and meansfor causing the contact-arms to snap dissimultaneously from stationarycontact to stationary contact.

8. The combination of a plurality of sets of annularly-arrangedstationary contacts, a cooperating contact-arm for each set, and meansfor causingthe contact-arms to snap from stationary contact tostationary contact.

9. The combination of a source of multiphase current, a rotary converterfed thereby, and means for successively varying the electromotive forcesimpressed upon the converter by the several phases of the multiphasecurrent.

10. The combination of a set of fixed contacts, means for maintainingsaid contacts at different potentials respectively, a movable contactcooperatively arranged with respect to said fixed contacts, and meansfor causing the movable contact to snap from one fixed contact toanother.

11. The combination of sets of contacts, a relatively movablecooperating contact-arm for each set, and means for causing thecontact-arms to snap dissimultaneously over their cooperating contacts.

12. The combination of a set of contacts, a relatively movable contactcooperating therewith, means for causing the relatively movable contactto move intermittently over said sets of contacts, and means for lockingsaid relatively movable-contact in various positions.

In witness whereof I have hereunto set my hand this 6th day of February,1900.

WILLIAM L. R. EMMET.

Witnesses:

BENJAMIN B. HULL, MABEL E. JACOBSON.

